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ii8                                        FERTILISERS

and blood, nails, hair, horns and the like), a number of handfuls are taken
from different parts of the mass and mixed as well as possible before the
sample is taken.

Liquid fertilisers or liquids with suspended or deposited matter are well
mixed with a stick.

The samples for analysis should be in three lots of at least 300 grams
each for powdered fertilisers or I kilo in other cases.

Powdered or pasty samples are placed in glass vessels with ground stop-
pers or tight corks, non-pulverulent samples in new bags or wooden boxes
and liquids in well cleaned bottles with new stoppers.

Each sample, duly sealed with sealing-wax, should bear a label indicating
the quality of the product, the quantity from which it was taken, the origin
and the date of sampling ; to this should be added a declaration of the sender
indicating the nature of the material sent or that for which it has been sold,
the strength (% of phosphoric anhydride, nitrogen, potash) guaranteed, and
the determinations required.

2. Preparation of the Sample in the Laboratory.- -'Before analysis,
the whole of the sample should be re-mixed and powdered to render it
homogeneous. If, however, the degree of fineness is to be determined, the
sample is mixed with a spatula, and the portion necessary for such test: set
aside, the rest being ground in a. mortar.

If the fertiliser contains hard lumps or pieces mixed with powder, it is

sieved through a. 0-5......i mm. sieve, the part remaining in the sieve being

powdered and re-sieved so as to obtain a. uniform powder, which is finally
thoroughly mixed.

Bones in lumps are broken in a mill or mortar and, if possible, powdered ;
if not they are first dried at a, low temperature (allowance being made for
the moisture lost).

Waste wool, hair, leather, and the like are. finely cut with scissors and
then mixed. Horns and nails may be powdered in an ordinary mill.

Stable manure and very wet or pasty fertilisers are dried at a. low tem-
perature and then mixed and powdered, account being taken of the moisture
lost (sec General Methods, 2, and Stable Manure).

GENERAL METHODS

These methods treat of certain preliminary tests and determinations
generally applicable, except where indicated, to the different types of
fertilisers.

1. Preliminary Tests

When the nature of a fertiliser is not definitely known, the following
tests are made in order to regulate thu subsequent determinations:

1.   Reaction,5 grams are mixed with 4* 5 c.c.  of water, and the
reaction of the liquid tested with litmus paper.

2.  Nitrogen.

(a) Ammoniacal Nitrogen, About i gram of the fertiliser is boiled with
5 c.c. of water and about 0-25 gram of calcined magnesia. : evolution of
ammonia indicates the presence of ammomaral nitrogen.up to about 90 % of sulphur, but high